Crossed-polars image of coesite grain (gray) ~1 mm across in eclogite. Small, colored inclusion is pyroxene. Polycrystalline rim is quartz.
General
Category
Tectosilicate, quartz group
Formula (repeating unit)
SiO2
IMA symbol
Coe[1]
Strunz classification
4.DA.35
Crystal system
Monoclinic
Crystal class
Prismatic (2/m) (same H–M symbol)
Space group
C2/c
Unit cell
a = 7.143 b = 12.383 c = 7.143 [Å] β = 120.00° Z = 16
Identification
Formula mass
60.0843 g/mol
Color
Colorless
Crystal habit
Inclusions in UHP metamorphic minerals up to 3 mm in size
Fracture
Conchoidal
Tenacity
Brittle
Mohs scale hardness
7.5
Luster
Vitreous
Streak
White
Diaphaneity
Transparent
Density
2.92 (calculated)
Optical properties
Biaxial
Refractive index
nx = 1.594 ny = 1.595 nz = 1.599
Birefringence
+0.006
2V angle
60–70
References
[2]
Coesite (/ˈkoʊsaɪt/)[3] is a form (polymorph) of silicon dioxide (SiO2) that is formed when very high pressure (2–3 gigapascals), and moderately high temperature (700 °C, 1,300 °F), are applied to quartz. Coesite was first synthesized by Loring Coes, Jr., a chemist at the Norton Company, in 1953.[4][5]
^Warr, L. N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
^Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C., eds. (1995). "Coesite" (PDF). Handbook of Mineralogy. Vol. 2 (Silica, Silicates). Chantilly, Virginia: Mineralogical Society of America. ISBN 0962209716. Retrieved December 5, 2011.
^Coes, Jr., L. (31 July 1953). "A New Dense Crystalline Silica". Science. 118 (3057): 131–132. Bibcode:1953Sci...118..131C. doi:10.1126/science.118.3057.131. PMID 17835139. The word coesite is pronounced as "Coze-ite", after chemist Loring Coes, Jr.
^Hazen, Robert M. (22 July 1999). The Diamond Makers. Cambridge University Press. p. 91. ISBN 978-0-521-65474-6. Retrieved 2012-06-06.
Coesite (/ˈkoʊsaɪt/) is a form (polymorph) of silicon dioxide (SiO2) that is formed when very high pressure (2–3 gigapascals), and moderately high temperature...
other deformation indicative of a hypervelocity extraterrestrial impact. Coesite, an indicator of shock metamorphism, was initially reported as being present...
associated in nature with two high-pressure polymorphs of silicon dioxide: coesite and stishovite. These polymorphs have a crystal structure different from...
cristobalite (high-temperature form), stishovite (high-pressure form), and coesite (high-pressure form). On the other hand, amorphous silica can be found...
polymorphs with all the members of the quartz group, which also include coesite, tridymite and stishovite. It is named after Cerro San Cristóbal in Pachuca...
almost 12 cm (5 in) in diameter; some of that pyrope has inclusions of coesite, and some has inclusions of enstatite and sapphirine. Pyrope is common...
produces rare ultrahigh pressure metamorphic minerals, such as coesite and stishovite. Coesite is rarely found in eclogite brought to the surface in kimberlite...
minerals such as tridymite and cristobalite, as well as the much less common coesite and stishovite. Biologically generated forms are also known as kieselguhr...
Teapot Ess in 1955. In 1960, Edward C. T. Chao and Shoemaker identified coesite (a form of silicon dioxide) at Meteor Crater, proving the crater was formed...
containing bits of dark glass, are found surrounding the lake. Some contain coesite, a high pressure mineral diagnostic of impact structures. The suevite is...
Quartz may occur as either of its two high-pressure forms, coesite and stishovite. Coesite occasionally occurs associated with eclogites formed during...
unshocked mineral grains, i.e. quartz, apatite, and zircon, as well as coesite. The difference in water content can be used to distinguish tektites from...
1955. In 1960, Edward C. T. Chao and Shoemaker identified shocked quartz (coesite) at Meteor Crater, proving the crater was formed from an impact generating...
impact. They include shatter cones and high-pressure minerals, for example coesite and stishovite. When a meteor strikes a planet's surface, the energy released...
and pellets. The impactite featured a form of shocked quartz known as "coesite", and is thus clearly the product of an impact event. The impact did not...
polymorphs, such as tridymite and cristobalite at high temperatures, and coesite at high pressures. Classifying minerals ranges from simple to difficult...
high-temperature polymorphs of SiO2 that occur in high-silica volcanic rocks. Coesite is a denser polymorph of SiO2 found in some meteorite impact sites and...
called silica or silicon dioxide) will first adopt a denser form known as coesite, then upon application of even higher pressure, form stishovite. These...
crater. A key discovery was the presence in the crater of the minerals coesite and stishovite, rare forms of silica found only where quartz-bearing rocks...
~200 °C under at least 10 kbar of pressure. The trigonal network undergoes a coesite-like transformation to monoclinic β-B2O3 at several gigapascals (9.5 GPa)...
crystalline forms of silica, SiO2. The most important forms of silica include: α-quartz, β-quartz, tridymite, cristobalite, coesite, and stishovite....
has original text related to this article: EB1911:Tridymite Cristobalite Coesite Stishovite Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical...
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